Masao Tsuji

Diffusion Tensor Imaging for Intracerebral Hemorrhage Outcome Prediction: Comparison Using Data from the Corona Radiata/Internal Capsule and the Cerebral Peduncle

BACKGROUND Magnetic resonance-diffusion tensor imaging (DTI) was used to predict motor outcome for patients with intracerebral hemorrhage. We compared the predictive accuracy of data sampled from the cerebral peduncle with data from the corona radiata/internal capsule. This study included 32 subjects with thalamic or putaminal hemorrhage or both. METHODS DTI data were obtained on days 14 to 18. Mean values of fractional anisotropy (FA) within the cerebral peduncle and the corona radiata/internal capsule were analyzed using a computer-automated method. Applying ordinal logistic regression analyses, the ratios between FA values in the affected and unaffected hemisphere (rFA) were modeled in relation to motor outcome scores at 1 month after onset, assessed using the Medical Research Council (MRC) scale (0 = null to 5 = full). RESULTS For both cerebral peduncle and corona radiata/internal capsule, the relationships between rFA and MRC matched logistic probabilities. While cerebral peduncle rFA values had statistically significant relationships with MRC scores (upper extremity R(2) = 0.271; lower extremity R(2) = 0.191), rFA values for the corona radiata/internal capsule showed less significant relationships (upper extremity R(2) = 0.085; lower extremity R(2) = 0.080). When estimated cerebral peduncle rFA values were <0.7, estimated probability of MRC 0 to 2 was close to 85% for the upper and 60% for the lower extremities. Meanwhile, when estimated rFA values were >0.9, estimated probability for MRC 4 to 5 nearly equaled 50% for the upper and 60% for the lower extremities. CONCLUSIONS FA values from within the cerebral peduncle more accurately predicted motor outcome and is a promising technique for clinical application.

Motor outcome for patients with acute intracerebral hemorrhage predicted using diffusion tensor imaging: an application of ordinal logistic modeling.

This study examined the clinical usefulness of magnetic resonance-diffusion tensor imaging (DTI) for predicting motor outcome in patients with intracerebral hemorrhage. We studied 15 subjects (age range, 31-81 years) diagnosed by conventional computed tomography with thalamic hemorrhage, putaminal hemorrhage, or both. DTI data were obtained on days 14-18 after diagnosis. Mean fractional anisotropy (FA) values within the right and left cerebral peduncles were estimated by a computer-automated method. Using logistic regression analyses, the ratios of FA values in the affected and unaffected hemispheres (rFA) were modeled in relation to motor outcome scores at 1 month after onset, assessed using the Medical Research Council (MRC) scale (0 = null to 5 = full). The rFA values ranged from 0.628 to 1.001 (median value, 0.856). Analyses showed that the relationships between rFA and MRC scale matched the logistic probabilities for both the upper extremities (R(2) = 0.272; P < .001) and lower extremities (R(2) = 0.247; P < .001). When estimated rFA values were <0.7, the estimated probability of an MRC score of 0-1 was close to 80% for the upper extremities and 65% for the lower extremities. Meanwhile, when estimated rFA values were >0.9, the estimated probability of an MRC score of 3-5 was close to 60% for the upper extremities and 80% for the lower extremities. Our data indicate that for patients with intracerebral hemorrhage, DTI is a useful tool for quantitatively predicting motor outcome, suggesting wider clinical applicability of this method for outcome prediction.

Neurenteric cyst of the lower clivus.

OBJECTIVENeurenteric cysts (NCs) typically arise as benign ventral intradural extramedullary developmental malformations of the spine which contain heterotopic epithelium resembling the intestinal or respiratory tracts. Intracerebral NCs are extremely rare, though the frequency of symptomatic reports and incidental findings is increasing, perhaps because of advances in neuroimaging. Recognition of the unique radiographic and histopathologic features of this entity is of growing importance in the treatment of cysts of the neural axis. We present an unusual case of an NC arising at the lower clivus. CLINICAL PRESENTATIONA 58-year-old man presented with occipitalgia, diplopia, a bilateral hearing deficit, and mild dysphagia. Computed tomography and magnetic resonance imaging demonstrated a 5 × 2 × 3-cm extra-axial cystic midline mass anterior to the brainstem at the lower clivus with posterior cyst wall enhancement. INTERVENTIONThe patient underwent a left lateral suboccipital total macroscopic resection of the lesion. Microscopic examination and histopathologic findings were consistent with a diagnosis of NC. CONCLUSIONWe describe the clinical presentation, imaging, and histopathologic characteristics, and discuss the diagnosis and surgical treatment of this rare lesion and related pathologic entities. Because of the remote possibility of delayed recurrence, even in cases of apparent total cyst wall removal, long-term serial imaging and a consideration of reoperation for recurrences is advisable.

Role of the endothelium on extraluminal and intraluminal vasoactive mechanisms in the perfused rabbit basilar artery.

In order to investigate the role of the endothelium in the regulation of cerebrovascular tone, we studied selective intraluminal and extraluminal vasoactive mechanisms of acetylcholine, potassium and serotonin. We also examined the effects of removal of the endothelium on these vasoactive responses. With 0.75 g of tension, isolated rabbit basilar arteries were fixed in a perfusion system with the ability to isolate the intraluminal and extraluminal surfaces, and perfused at 8 ml-1 min-1 under a pressure of 8 mmHg. To remove the endothelium, we applied several concentrations of saponin. The endothelium was completely removed by 0.05 mg-1 ml-1 saponin, confirmed histologically. Extraluminal and intraluminal acetylcholine induced endothelium-dependent relaxations. Intraluminal potassium induced greater contraction than extraluminal potassium in both saponin denuded (p < 0.01) and intact preparations (p < 0.05, n = 8). Intraluminal and extraluminal serotonin induced symmetric contractions, and for both sides the response was enhanced by removal of the endothelium (p < 0.05, n = 6). Our results suggest that inhibitory (relaxant) contribution of the endothelium to contractile responses varies depending on the vasoactive agent. The fact that the effects of some extraluminal agents were enhanced when the endothelium was denuded, may be of some importance in potentiating the mechanism of vasospasm following subarachnoid haemorrhage.

Development of a new perfusion system for pharmacological study on rabbit basilar arteries.

We developed a constant-flow perfusion system to measure vascular responses to vasoactive agents applied intraluminally or extraluminally. The intraluminal and extraluminal sides of a cylindrical section of rabbit basilar artery were isolated completely. By loading with 0.75 g of tension, the resting condition of each preparation was made constant. The intraluminal side was perfused at a constant flow of 8 ml/min and under an intraluminal pressure of 8 mm Hg. When 30 mM KCl was administered intraluminally the preparation showed marked contraction, whereas only slight contraction was observed with extraluminal administration. When 2 x 10(-7) M 5-hydroxytryptamine was administered, no significant differences in contraction could be detected between the intraluminal and extraluminal routes. Application of 10(-6) to 10(-4) M acetylcholine after precontraction with 30 mM KCl resulted in much stronger dilatation upon intraluminal application. Thus, it was demonstrated that under certain conditions significant differences exist in the responses of rabbit basilar arteries to vasoactive agents applied intraluminally or extraluminally. This system can detect the effects of vasoactive agents administered intraluminally and extraluminally at a high level of sensitivity and shows good reproducibility as a means of analyzing vascular functions and characteristics.

Remote cerebellar hemorrhage after supratentorial unruptured aneurysmal surgery: report of three cases

Abstract We report three cases of remote cerebellar hemorrhage that developed after supratentorial unruptured aneurysmal surgery. In all cases, digital subtraction angiography was performed before each operation in order to rule out other vascular abnormalities, especially around the operative field or the posterior circulation. In addition, all patients were screened for any previous history of bleeding tendencies or other related medical disorders. Each patient underwent clipping surgery via the pterional approach. Remote cerebellar hemorrhage was identified on post-operative computed tomographic scans. In all cases, there was no evidence of significant associated long-term morbidity. A consideration of the possible pathophysiologic mechanisms underlying these post-operative remote cerebellar hemorrhages and suggested strategies for avoiding such complications are discussed.

Effect of Ebselen on Contractile Responses in Perfused Rabbit Basilar Artery

OBJECTIVE To evaluate the possible role of the antioxidant ebselen in the treatment of cerebral vasospasm, we examined the effects of ebselen on the vasoactive mechanisms induced by endothelin (ET)-1, oxyhemoglobin, and oxygen-derived radicals. METHODS Isolated rabbit basilar arteries with intact endothelium were fixed in a perfusion system and perfused intraluminally. Contraction of the artery was detected as an increase in perfusion pressure. RESULTS Ebselen, in a certain concentration range (3 x 10(-6) and 10(-5) mol/L), significantly reduced the contractile response to ET-1 (10(-10) to 10(-8) mol/L) but not the contraction induced by 40 mmol/L potassium. It reduced the contraction induced by 10(-4) mol/L 1,2-dioctanoyl-sn-glycerol, a protein kinase C activator. Addition of 10(-5) mol/L dithiothreitol, a sulfhydryl-reducing agent, partially reversed the inhibitory effects of ebselen on ET-1- and 1,2-dioctanoyl-sn-glycerol-induced contractions. Ebselen (10(-5) mol/L) as well as a combination of catalase (1000 units/mL) and superoxide dismutase (150 units/mL) inhibited the potentiating effects of oxyhemoglobin (10(-5) mol/L) on ET-1-induced contraction. Both ebselen and catalase inhibited the contractile response to hydroxyl radical generated by ferrous ion (10(-3) mol/L) plus hydrogen peroxide (10(-2) mol/L). Ebselen reduced the response to potassium when a high dose (3 x 10(-5) mol/L) was applied and failed to preserve contractility of the preparation after exposure to hydroxyl radical. CONCLUSION Ebselen suppressed ET-1-induced contraction and synergetic interaction between oxyhemoglobin and ET-1, where free radical formation was involved. These effects may result from modification of the intracellular regulatory system including protein kinase C, as well as from protection against free radicals.

Pressure gradients between intraluminal and extraluminal spaces may affect the potassium induced contraction in the rabbit’s basilar arteries

In order to investigate the different contactile effects between intraluminal and extraluminal vasoactive agents, we studied the contractile responses of rabbit basilar artery to selective intraluminal and extraluminal administration of potassium, serotonin and histamine in vitro. We also studied how the physical pressure gradients, such as hydrostatic or osmotic pressure gradients between intraluminal and extraluminal spaces, affect potassium-induced contraction. Intraluminal potassium (30 mM) induced a significantly greater contraction than extraluminal potassium. Serotonin (2 x 10(-7) M) and histamine (10(-5) M) applied intraluminally caused the same magnitude of the contraction as those applied extraluminally and no significant differences were noted between these applications. These differences in potassium-induced contraction were more significant when the intraluminal hydrostatic pressure was elevated by 20 mmHg. Contraction by either intraluminal or extraluminal potassium was significantly decreased when intraluminal pressure was raised by 40 mmHg. As the osmotic pressure gradients between the extraluminal and the intraluminal spaces were increased, these differences in potassium-induced contraction were decreased. Our findings suggest that physical pressure gradients may affect potassium-induced contraction in a different manner from pharmacologically-induced contraction and that free ions can penetrate the vascular wall by physical pressure gradients between the intraluminal and extraluminal spaces of cerebral artery.

Arteriovenous malformation of the vestibulocochlear nerve.

We describe a rare case of an arteriovenous malformation (AVM) embedded in the vestibulocochlear nerve presenting with subarachnoid hemorrhage (SAH) treated by microsurgical elimination of the main feeding artery and partial nidus volume reduction with no permanent deficits. This 70-year-old woman was incidentally diagnosed 4 years previously with two small unruptured tandem aneurysms (ANs) on the right anterior inferior cerebral artery feeding a small right cerebellopontine angle AVM. The patient was followed conservatively until she developed sudden headache, nausea and vomiting and presented to our outpatient clinic after several days. Magnetic resonance imaging demonstrated findings suggestive of early subacute SAH in the quadrigeminal cistern. A microsurgical flow reduction technique via clipping between the two ANs and partial electrocoagulation of the nidus buried within the eighth cranial nerve provided radiographical devascularization of the ANs with residual AVM shunt flow and no major deficits during the 2.5 year follow-up. This is only the second report of an auditory nerve AVM. In the event of recurrence, reoperation or application of alternative therapies may be considered.

Endoscopic third ventriculostomy for hydrocephalus due to unruptured pineal AVM: case report and review of the literature.

INTRODUCTION Arteriovenous malformations (AVM) are considered to be static congenital lesions; however, a subset may possess dynamic pathophysiological capabilities of growth, regression or other morphological changes with time. We report on an adult patient harboring a pineal AVM who presented with progressive symptoms of obstructive hydrocephalus and was successfully treated by endoscopic third ventriculostomy (ETV). CLINICAL PRESENTATION This 63-year-old man was incidentally diagnosed 8 years previously with an asymptomatic unruptured pineal AVM and followed conservatively until he developed a progressive impairment in consciousness with gait apraxia and incontinence over a period of 2 months. Magnetic resonance imaging (MRI) revealed obstructive hydrocephalus due to nidal compression at the level of the aqueduct. Treatment by ETV resulted in resolution of neurological deficits and ventriculomegaly without evidence of complications at 18-months follow-up. CONCLUSION Treatment by ETV in adults with obstructive hydrocephalus due to deep pineal AVMs is a reasonable option in selected cases. A discussion of the pathological mechanisms and therapeutic options for this rare entity is presented.